Airworthiness Directives; McDonnell Douglas Model DC-9-10, DC-9-20, DC-9-30, DC-9-40, and DC-9-50 Series Airplanes, Equipped With a Tail Cone Evacuation Slide Container Installed in Accordance With Supplemental Type Certificate (STC) ST735SO

[Federal Register Volume 73, Number 233 (Wednesday, December 3, 2008)]
[Rules and Regulations]
[Pages 73545-73547]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-27937]



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Federal Register / Vol. 73, No. 233 / Wednesday, December 3, 2008 / 
Rules and Regulations

[[Page 73545]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-28881; Directorate Identifier 2006-NM-263-AD; 
Amendment 39-15663; AD 2008-18-06]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model DC-9-10, DC-9-
20, DC-9-30, DC-9-40, and DC-9-50 Series Airplanes, Equipped With a 
Tail Cone Evacuation Slide Container Installed in Accordance With 
Supplemental Type Certificate (STC) ST735SO

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: We are adopting a new airworthiness directive (AD) for 
McDonnell Douglas Model DC-9-10, DC-9-20, DC-9-30, DC-9-40, and DC-9-50 
series airplanes, equipped with tail cone evacuation slide containers 
as specified above. This AD requires modifying the tail cone slide. 
This AD also requires additional tail cone drops and slide deployments, 
and repair if necessary. This AD results from several reports of 
inadvertent tail cone deployments in which the tail cone slide failed 
to deploy. We are issuing this AD to ensure that the tail cone 
evacuation slide deploys correctly. Failure of the slide to deploy 
during an emergency evacuation could result in injury to flightcrew and 
passengers.

DATES: This AD is effective January 7, 2009.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this AD, the regulatory evaluation, 
any comments received, and other information. The address for the 
Docket Office (telephone 800-647-5527) is the Document Management 
Facility, U.S. Department of Transportation, Docket Operations, M-30, 
West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Ken Sujishi, Aerospace Engineer, Cabin 
Safety Branch, ANM-150L, FAA, Los Angeles Aircraft Certification 
Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; 
telephone (562) 627-5353; fax (562) 627-5210.

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to include an airworthiness directive (AD) that would apply to 
McDonnell Douglas Model DC-9-10, DC-9-20, DC-9-30, DC-9-40, and DC-9-50 
series airplanes, equipped with certain tail cone evacuation slide 
containers. That NPRM was published in the Federal Register on August 
6, 2007 (72 FR 43578). That NPRM proposed to require modifying the tail 
cone slide. That NPRM also proposed to require additional tail cone 
drops and slide deployments, and repair if necessary.

Comments

    We gave the public the opportunity to participate in developing 
this AD. We considered the comments received from the one commenter.

Request To Clarify Paragraph (g) of the NPRM

    Northwest Airlines (NWA) requests that we clarify whether the 150-
flight-cycle compliance time specified in paragraph (g) of the NPRM 
starts after the first airplane is modified or after the last airplane 
is modified. Unless the FAA intends to have operators perform slide 
deployments while the fleet is still being modified, NWA recommends 
that the 150-flight-cycle clock start after the modification, or within 
24 months after the effective date of the AD, whichever occurs first. 
NWA also states that it assumes the 150-day compliance clock in that 
same paragraph is intended for those operators who have already 
complied with the intent of the AD or who will comply very quickly 
after issuance of the AD. NWA states that it would be helpful if this 
was stated.
    We agree with NWA's request for clarification. Our intent was for 
the operator to start and complete the tail cone modification and fly a 
minimum of 150 flight cycles before the additional tail cone deployment 
test, accomplished within 24 months after the effective date of the AD. 
When there are multiple airplanes, the 150 flight cycles apply to each 
individual airplane, and start after the modification is done to each 
airplane individually.
    Scenario: An operator completes the modification on the first 
airplane, and then completes the minimum 150 flight cycles two months 
after the modification. After the operator successfully performs the 
tail cone slide deployment test on the first airplane, the second 
airplane is modified a week later. The second airplane will also be 
required to fly a minimum of 150 flight cycles before the deployment 
test of the tail cone slide. If the operator has 100 airplanes, then 
the operator must demonstrate a successful deployment test on 10 
percent (ten) of the modified airplanes as terminating action for the 
AD.
    We agree that the proposed 150-day compliance time specified in 
paragraph (g) of the NPRM needs not only to be clarified, but also 
revised. The 150-day requirement could impose a schedule hardship for 
some operators who might need more time to complete the modification. 
Our intent was to allow the operator time to modify the tail cone slide 
cover and to perform the deployment test after a minimum of 150 flight 
cycles after modification, and no later than 24 months after the 
effective date of this AD.
    For all these reasons, we have revised paragraph (g) and added a 
new paragraph (h) to the AD to clarify the compliance time. The new 
paragraph (g) begins as follows: ``* * * no earlier than 150 flight 
cycles after doing the modification required by paragraph (f) of this 
AD, and no later than 24 months after the effective date of this AD. * 
* *'' The new paragraph (h) states that operators should contact the 
Manager, Los Angeles Aircraft Certification Office (ACO), FAA, if the

[[Page 73546]]

repeat deployment cannot be performed as required by paragraph (g) of 
this AD.

Request for Exemption From Proposed Requirements

    NWA also requests exemption from the proposed requirements of 
paragraph (g) of the NPRM. NWA states that while performing testing to 
obtain Supplemental Type Certificate (STC) ST01967CH, it successfully 
performed 5 tail cone drops and slide deployments with the new design 
slide installation. NWA believes that the requirement to perform 
additional slide deployments is arbitrary, and that the 5 tail cone 
drops performed as part of the STC approval are sufficient to prove the 
design reliability of its airplanes.
    We disagree with the request for exemption. The 5 tail cone drops 
and slide deployments that NWA did during the STC approval process did 
not represent the severity of the actual operating environment for the 
tail cone, including temperature and high takeoff and landing loads, 
nor did they represent repeated flight cycles with various types of 
contamination such as dirt and fuel. Tail cone slides must be 
overhauled, repacked and re-rigged every 3 years and have no other 
maintenance requirements in order to verify successful deployment. We 
have not changed the AD in this regard.

Explanation of Change to Paragraph (f) and Removal of Note 1 of the 
NPRM

    We have revised paragraph (f) of this AD, and have removed Note 1 
of this AD, to remove reference to Northwest Airlines STC ST01967CH and 
Northwest Airlines Drawing 9B25-41477, Revision B, dated September 14, 
2006; and Northwest Airlines Drawing 9B25-90399, Revision D, dated 
December 21, 2006. However, we have approved Northwest Airlines STC 
ST01967CH as a method for modifying the tail cone slide. Operators may 
contact the Manager, Los Angeles ACO, for information regarding 
Northwest Airlines STC ST01967CH for modifying the tail cone slide, as 
required by paragraph (f) of this AD.

Conclusion

    We reviewed the relevant data, considered the comment received, and 
determined that air safety and the public interest require adopting the 
AD with the changes described previously. We also determined that these 
changes will not increase the economic burden on any operator or 
increase the scope of the AD.

Costs of Compliance

    There are about 400 airplanes of the affected design in the 
worldwide fleet. This AD affects about 300 airplanes of U.S. registry. 
The tail cone drops/slide deployments take about 16 work hours per 
airplane, at an average labor rate of $80 per work hour. Required parts 
cost about $1,300 per airplane. Based on these figures, the estimated 
cost of the AD for U.S. operators is $774,000, or $2,580 per airplane.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. ``Subtitle VII: Aviation Programs'' 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
``Subtitle VII, Part A, Subpart III, Section 44701: General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    This AD will not have federalism implications under Executive Order 
13132. This AD will not have a substantial direct effect on the States, 
on the relationship between the national government and the States, or 
on the distribution of power and responsibilities among the various 
levels of government.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979), and
    (3) Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.
    You can find our regulatory evaluation and the estimated costs of 
compliance in the AD Docket.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.

Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new AD:

2008-18-06 McDonnell Douglas: Amendment 39-15663. Docket No. FAA-
2007-28881; Directorate Identifier 2006-NM-263-AD.

Effective Date

    (a) This airworthiness directive (AD) is effective January 7, 
2009.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to McDonnell Douglas Model DC-9-11, DC-9-12, 
DC-9-13, DC-9-14, DC-9-15, DC-9-15F, DC-9-21, DC-9-31, DC-9-32, DC-
9-32 (VC-9C), DC-9-32F, DC-9-33F, DC-9-34, DC-9-34F, DC-9-32F (C-9A, 
C-9B), DC-9-41, and DC-9-51 airplanes, certificated in any category, 
equipped with a tail cone evacuation slide container installed in 
accordance with supplemental type certificate (STC) ST735SO.

Unsafe Condition

    (d) This AD results from several reports of inadvertent tail 
cone deployments in which the tail cone slide failed to deploy. We 
are issuing this AD to ensure that the tail cone evacuation slide 
deploys correctly. Failure of the slide to deploy during an 
emergency evacuation could result in injury to flightcrew and 
passengers.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Initial Actions to Address Slide Deployment Failures

    (f) Within 24 months after the effective date of this AD: Modify 
the tail cone slide in accordance with a method approved by the 
Manager, Los Angeles Aircraft Certification Office (ACO), FAA.

Repeat Deployment and Terminating Action

    (g) Except as provided by paragraph (h) of this AD, no earlier 
than 150 flight cycles after doing the modification required by 
paragraph (f) of this AD, and no later than 24 months after the 
effective date of this AD: Do additional tail cone drops and slide 
deployments on a minimum of 10 percent of an operator's fleet of 
affected airplanes (if fewer than 10 airplanes in the fleet: at 
least one airplane).

[[Page 73547]]

    (1) If the tailcone and slide deployments are successful 
according to the applicable McDonnell Douglas DC-9 airplane 
maintenance manual, no further action is required by this AD.
    (2) If any tailcone and slide deployment is unsuccessful 
according to the applicable McDonnell Douglas DC-9 airplane 
maintenance manual, before further flight, repair in accordance with 
a method approved by the Manager, Los Angeles ACO, FAA.

Exception to Compliance Time for Repeat Deployment

    (h) For any airplane on which the repeat tail cone drop 
deployment cannot be performed within 24 months after the effective 
date of this AD as required by paragraph (g) of this AD: Repeat the 
deployment as approved by the Manager, Los Angeles ACO, FAA, in 
accordance with the procedures specified in paragraph (i) of this 
AD.

Alternative Methods of Compliance (AMOCs)

    (i)(1) The Manager, Los Angeles ACO, FAA, ATTN: Ken Sujishi, 
Aerospace Engineer, Cabin Safety Branch, ANM-150L, 3960 Paramount 
Boulevard, Lakewood, California 90712-4137; telephone (562) 627-
5353; fax (562) 627-5210; has the authority to approve AMOCs for 
this AD, if requested using the procedures found in 14 CFR 39.19.
    (2) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Before using any approved AMOC on any airplane to which the AMOC 
applies, notify your appropriate principal inspector (PI) in the FAA 
Flight Standards District Office (FSDO), or lacking a PI, your local 
FSDO.

Material Incorporated by Reference

    (j) None.

    Issued in Renton, Washington, on November 16, 2008.
Stephen P. Boyd,
Assistant Manager, Transport Airplane Directorate, Aircraft 
Certification Service.
[FR Doc. E8-27937 Filed 12-2-08; 8:45 am]
BILLING CODE 4910-13-P

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